One conventional way of mechanical actuating circuit-breakers is to make use of a compression spring. The energy required for a maneuver is then stored in the spring while in the compressed state. The spring is held in the compressed state by a latching device which may be more or less complex, and which necessarily includes a latching member which prevents a wheel or a cam from moving.
In this respect, reference may be made to French Pat. No. 1 588 485. This French Pat. No. 1 588 485 describes a spring device controlled by impulses in order to maneuver electrical apparatuses, in particular circuit-breakers or isolators, with the maneuvering time being long relative to the duration of the controlling pulse. This device comprises a spring which drives a tripping control shaft via a cable and a cam. The device is reset by means of a shaft provided with non-return means comprising, in particular, a ratchet wheel cooperating with a pawl carrying a latching wheel at its end and driving said control shaft via a step-down drive chain in a direction opposite to the tripping direction. The pulse causes the non-return means to be held back permanently, thereby allowing tripping to be completed.
The latching member and the ratchet wheel exert a mutual force between each other and this force must be overcome in order to release the wheel and allow the spring to expand. The greater the amount of energy stored in the springs, the greater the force to be overcome, and the greater the force to be overcome the greater the amount of energy required by the trigging mechanism.
Unfortunately, it is desirable to use a low-energy tripping mechanism.
It is also desirable to be able to increase the quantity of stored energy (for example by using a plurality of springs and/or by using more powerful springs), without increasing the latching force.
This aim is achieved by the device in accordance with the invention which makes it possible to store mechanical energy with a zero latching force.